Incoherent scatter radar observations during August 4–7, 1972

The incoherent scatter radar installation at Chatanika, Alaska (Λ = 65°) has been used to investigate ionospheric conductivities, electric fields, and electron densities during the extraordinarily large magnetospheric disturbances of August 4–7, 1972. It is found that following two sudden commencements which occurred on August 4 while Chatanika was in the afternoon sector, the polar cusp moved equ...